Tunnel use facilitates handling of ICR mice and decreases experimental variation.

We evaluated a handling method using tunnels to tame laboratory mice (ICR) in the context of animal welfare and ease of handling. During 1-week acclimation to handling and subsequent 1-week oral administration (once per day), voluntary interaction with the experimenter was much greater in mice handled by a tunnel compared to those picked up by the tail. According to a rating of the ease of handling laboratory mice, a tunnel facilitated mouse handling during acclimation to handling and oral gavage of saline compared to tail handling. In addition, mice handled by a tunnel showed less anxiety than mice handled by the tail in the open field test, but not in elevated plus maze. Calculation of experimental variation in behavioral tests, which were used to mimic pharmacological studies, suggested that mice handled by a tunnel exhibited the tendency of less variation compared to those picked up by the tail, in both groups that were intraperitoneally administered saline as placebo and diazepam as an active drug. Thus, tunnel use could be beneficial for improving animal welfare and facilitated handling of ICR mice in mouse studies.